Exercise devices are known, often popularly called “sleds”, which comprise a ground engaging frame that the user moves over a substantially horizontal support surface, such as the ground or a floor, to build leg and upper body strength. In many cases, such a sled includes handles which the user, who is standing behind the sled, grips and pushes forwardly against to push the sled over the support surface in a generally forward direction of motion. In other cases, the sled includes some type of harness which the user, who is now standing ahead of the sled, wears to pull or drag the sled behind the user in a generally forward direction of motion as the user moves forwardly. In most cases, the frame includes means for adjusting the total weight thereof to increase or decrease the effort required from the user to move the frame over the support surface. The effort required is greater when the total weight of the frame is increased and is lesser when the total weight of the frame is decreased. U.S. Pat. Nos. 7,727,089 and 7,955,223 to Gilman are typical examples of push type exercise sleds.
Most exercise sleds, including those referenced above and issued to Gilman, adjust the total weight of the sled by having some type of vertically extending peg or pin on which a plurality of conventional barbell type weight plates can be stacked. Thus, the total weight of the sled varies depending upon how many weight plates it carries. The total weight of the sled is obviously higher when the sled carries more weight plates and is lower when the sled carries fewer weight plates. To allow the total weight of the sled to vary over a relatively large range, the peg or pin carrying the weight plates has to be long enough to accommodate a large number of weight plates, or multiple pegs or pins have to be provided on the frame, or each of the weight plates has to be relatively heavy, or some combination of the above.
While this is a workable way of varying the total weight of the sled, it has a number of disadvantages. For one thing, if heavy weight plates, such as 45 pound weight plates are used, then the total weight of the sled can be adjusted in only relatively large, e.g. 45 pound, increments, with adjustments in between not being possible. If smaller weight plates are used, many more of these weight plates have to be on hand and accessible for stacking to get to a total weight that is large enough. In addition, the frame of the sled must be provided with many more pegs or pins for carrying such weight plates.
In addition, if a user selects a very heavy total weight for the sled and then moves the sled a considerable distance over the support surface, the user might decide that the same very heavy total weight is now too much for the user to move over the return trip back to the starting point due to the effort the user expended in the first half of the trip. The only way to lessen the total weight of the sled in this eventuality is for the user to offload some of the weight plates before moving the sled back to the starting point. Unfortunately, this leaves the offloaded weight plates at some distance away from the starting point and requires the user to subsequently go and retrieve them. Accordingly, a way of easily adjusting the effort required by the user to move the sled that would avoid these disadvantages would be an advance in the art.
Other exercise devices that are somewhat related to the sleds described above are wheelbarrow type devices which comprise a frame that incorporates a ground engaging wheel at one end of the frame. Such exercise wheelbarrows lack the typical material carrying bucket or hopper found on the types of wheelbarrows found in lawn and garden stores. Instead, the frame of the exercise wheelbarrow carries the types of pegs or pins typically found on exercise sleds for being able to load a selected number of weight plates onto the exercise wheelbarrow to adjust the total weight thereof.
The exercise wheelbarrow typically has two rearwardly extending, laterally spaced, elongated handles on the end of the frame opposite to the end of the frame that carries the wheel. The user grips these handles towards the outer end thereof, lifts up on the handles to lift the total weight of wheelbarrow up off the ground and place such weight on the ground engaging wheel, and then pushes forwardly on the handles in the manner of a typical wheelbarrow to roll the exercise wheelbarrow forwardly on its wheel. The effort required from the user to do this is a function of how many weight plates are stacked on the pegs or pins carried on the frame of the wheelbarrow and where such pegs or pins are placed on that frame. U.S. Pat. No. 8,858,405 to Agate shows an exercise wheelbarrow of this type.
To the extent that exercise wheelbarrows simply use pegs or pins for carrying a selected number of stacked weight plates in order to adjust the total weight of the wheelbarrow, exercise wheelbarrows suffer the same weight adjustment disadvantages as their exercise sled brethren. Thus, a way of easily adjusting the effort required by the user to move an exercise wheelbarrow without suffering from these same disadvantages would also be an advance in the art.
Finally, exercise sleds and exercise wheelbarrows are typically built and sold as entirely separate devices. A user wishing to have both devices on hand for use in exercising would have to buy both devices separately, namely both a sled as well as a separate wheelbarrow. The Agate patent referenced above discloses a single device that is convertible between sled and wheelbarrow configurations.
However, the manner of construction of the Agate device and the nature of the conversion is unduly complicated and somewhat cumbersome. For example, separate handle styles having separate parts need to be used in the Agate device depending upon whether one is in the sled or in the wheelbarrow configuration. These separate handles are prone to being lost on unavailable when needed. In addition, the Agate device uses the traditional peg or pin/stacked weight plate method of total weight adjustment and thus suffers from the weight adjustment disadvantages discussed above.